PROJECT SUMMARY The Cardiothoracic Surgical Trials Network (CTSN) has made significant contributions in advancing the evidence base for cardiothoracic surgery. As the population ages and the incidence of cardiovascular disease remains high, there is an important public health need to expand the capacity of the CTSN. Northern New England (NNE) is home to the most rural and elderly population in the US. Individuals living in NNE are medically underserved and face significant socioeconomic challenges. These conditions occur in the context of higher rates of comorbid conditions, leading to a high cardiovascular disease burden and lower life expectancy. Importantly, rural patients are underrepresented in cardiovascular clinical trials. As hospitals located in NNE, Dartmouth-Hitchcock Medical Center (DHMC) and Maine Medical Center (MMC) share a common goal of improving the health of rural communities. Specific aims are: (1) to expand the capacity of the CTSN in rural populations with high cardiovascular disease burden and develop strategies for implementing trial findings in such patients; (2) to support the development and clinical research capacity at MMC; and (3) to train the next generation of implementation science researchers through the Clinical and Implementation Research Skills Program (CIRSP). Several unique features of this collaboration will allow achievement of these aims. First, DHMC and MMC are the major referral centers for cardiac surgery in NNE, ensuring an ideal setting for recruiting patients with a high cardiovascular disease burden. Second, DHMC is an international leader in the use of regional and national registries to facilitate population-based research. DHMC is the data coordinating center for Northern New England Cardiovascular Disease Study Group (NNECDSG) which collects data on 90% of cardiac surgery in NNE. DHMC also maintains the largest non- federal repository of Medicare data in the US through the Dartmouth Atlas. Third, Dr. Iribarne has 11 years of experience with the CTSN and brings significant knowledge of lessons learned on optimal recruitment strategies for enrolling cardiac surgery patients. Fourth, DHMC and MMC have worked collaboratively in quality improvement since 1987 through the NNECDSG; the Linked Clinical Research Center (LCRC) program is a natural extension of this collaboration. Fifth, a group of nationally recognized experts in implementation science has been assembled to educate CIRSP Scholars in late-stage implementation research. The expected results are that: (1) the capacity of the CTSN will expand into rural populations with high cardiovascular disease burden; (2) implementation science will be integrated in future CTSN research; (3) MMC will be a leading enroller in CTSN trials; and (4) early career investigators will be trained in and perform late-stage implementation research using the CTSN infrastructure. These results will support the mission of the LCRC program in expanding the capacity of cardiothoracic surgery research in areas of need.